Using amsmath to "minimise" the example in what sense?
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ptrcaoOct 1 '11 at 0:01

1

@ptrcao The siunitx package is not necessary to see the problem, you only need to ensure that align* is defined. Thus I'm loading the minimum number of packages to show the problem. (Add \listfiles to the original and to my example, and the list of packages will be much shorter for the later.)
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Joseph Wright♦Oct 1 '11 at 6:46